In general, in the outer area in house construction, especially on roofs or on facades, sheeting, especially plastic sheeting, or also boards, especially made from hardwood, are installed as so-called “wind resistance” or “rain protection.” Such coverings lie above the insulation layer and below the actual outer layer, which is composed, e.g., from bricks, cement-asbestos boards, or the like. As a rule, this cover layer is laid in an overlapping arrangement, with the resulting joints being bonded with one-sided adhesive strips. In this way, penetration of wind, snow, rain, or the like between the outer layer into open joints and production of air currents in the area of the insulation layer can be prevented. Such air currents of cold outside air would reduce the insulation effect, which is to be prevented as much as possible.
In general, for the bonding of sheeting in the outer area in house construction, according to the state of the art usually one-sided adhesive strips are used, which feature, in particular, carriers made from polyethylene sheeting, PVC sheeting, or thermally compressed non-woven spun carrier sheeting.
In general, sheeting or boards used in the outer area in house construction are very vapor permeable, with these usually having an sd value of ≦1 m, measured according to DIN 52615. The adhesive strips widely used and known from the state of the art for bonding joints of such boards or sheeting usually exhibit an essentially higher water-vapor diffusion resistance and usually have sd values that are significantly higher than the corresponding values of sheeting or boards that are used; for example, such values for adhesive strips that are used in the state of the art lie in the range from 20-50 m. In practice, it has been shown in the use of such adhesive strips of the state of the art that for a discharge of diffusing water vapor, e.g., from the roof construction of a house, due to trapped building moisture or residual moisture of construction wood, the moisture in areas, in which there is no joint bonding of the state of the art, can escape easily through the very vapor permeable sheeting or boards, but condensation water can build up along the joint bonding in the area directly under a joint bond with adhesive strips of the state of the art due to the significantly more diffusion-tight adhesive strip in this area. Thus, according to the downward diffusion slope, it can lead to a considerable collection of water, which, as a consequence, can cause rot and structural damage. This is the case, in particular, when more moisture is flowing in from below than can leak out due to the increased diffusion resistance from the joint bonding of the state of the art. Such moisture can involve trapped residual moisture in the roof due to moist construction wood or moisture in the air, which always flows back into the roof construction due to the inner vapor barrier that is not sealed airtight everywhere.
Especially for the use of sheeting as an additional wind and rain protection layer in the outer area in house construction, there is the additional problem that this sheeting must be stretched in webs over the entire roof construction or along the entire width or height of the fagade, so that undulations in individual sheeting webs due to different tensioning can scarcely be avoided. In the area of the joints between two webs, which are tensioned differently or have corresponding undulations, it is thus actually very desirable that adhesive strips be used that provide soft, conforming, and stretching carrier materials that are, however, also sufficiently stable. Otherwise, when laying such sheeting, joint areas that may have been bonded tightly together can detach due to the inherent restoring force of the sheeting material and over time a leakage point can appear in the bonding. Very soft and flexible carrier materials for self-adhesive strips have the advantage that they can continuously conform to all unevenness, but the processability and stability of such carriers often suffers due to the relative softness and excessive flexibility.
Thus, different, actually prohibitive requirements are given with the bonding of sheeting in the outer area in house construction for adhesive strips to be used there.
For example, if one uses an adhesive strip according to the state of the art, which uses as the carrier material a so-called plastic membrane composed of, for example, a polymer sheeting that is mechanically stretched and thus has microscopic openings, such an adhesive strip of the state of the art does obtain permeability, but it loses its stretching ability and elasticity, consequently also its mechanical loading capacity, which has the effect that such an adhesive strip would tear too quickly. In addition, such an adhesive strip would no longer be water tight, because rainwater could pass through the microscopic openings, which could also lead over time to detachment of the adhesive that is used. If one uses as the carrier material for adhesive strips of the state of the art a non-woven carrier, then a high permeability is reached but such an adhesive strip would also no longer be able to conform and as a rule would no longer be water tight. If one uses a coating on such a non-woven carrier, it would be water tight, but it would become even more inflexible and would not conform, which would lead to the problems mentioned above when bonding joints of sheeting in the outer area in house construction.